Preserving access to an Amazon Machine Image (AMI) for a retired platform

#!/bin/bash

set -ue

USAGE="This script is used to copy an AMI used by your Elastic Beanstalk environment into your account to use in your environment.\n\n" 
USAGE+="Usage:\n\n"
USAGE+="./$(basename $0) [OPTIONS]\n"
USAGE+="OPTIONS:\n"
USAGE+="\t--application-name <application-name>\tThe name of your Elastic Beanstalk application.\n"
USAGE+="\t--environment-name <environment-name>\tThe name of your Elastic Beanstalk environment.\n"
USAGE+="\t--region <region> \t\t\tThe AWS region your Elastic Beanstalk environment is deployed to.\n"
USAGE+="\n\n"
USAGE+="Script Usage Example(s):\n"
USAGE+="./$(basename $0) --application-name my-application --environment-name my-environment --region us-east-1\n"

if [ $# -eq 0 ]; then
  echo -e $USAGE
  exit
fi

while [[ $# -gt 0 ]]; do
  case $1 in
    --application-name)       APPLICATION_NAME="$2"; shift ;;
    --environment-name)       ENVIRONMENT_NAME="$2"; shift ;;
    --region)                 REGION="$2"; shift ;;
    *)                        echo "Unknown option $1" ; echo -e $USAGE ; exit ;;
  esac
  shift
done

aws_cli_version="$(aws --version)"
if [ $? -ne 0 ]; then
  echo "aws CLI not found. Please install it: https://docs.aws.amazon.com/cli/latest/userguide/getting-started-install.html. Exiting."
  exit 1
fi
echo "Using aws CLI version: ${aws_cli_version}"

account=$(aws sts get-caller-identity --query "Account" --output text)
echo "Using account ${account}"

environment_ami_id=$(aws elasticbeanstalk describe-configuration-settings \
  --application-name "$APPLICATION_NAME" \
  --environment-name "$ENVIRONMENT_NAME" \
  --region "$REGION" \
  --query "ConfigurationSettings[0].OptionSettings[?OptionName=='ImageId'] | [0].Value" \
  --output text)
echo "Image associated with environment ${ENVIRONMENT_NAME} is ${environment_ami_id}"

owned_image=$(aws ec2 describe-images \
  --owners self \
  --image-ids "$environment_ami_id" \
  --region "$REGION" \
  --query "Images[0]" \
  --output text)
if [ "$owned_image" != "None" ]; then
  echo "${environment_ami_id} is already owned by account ${account}. Exiting."
  exit
fi

source_image_name=$(aws ec2 describe-images \
  --image-ids "$environment_ami_id" \
  --region "$REGION" \
  --query "Images[0].Name" \
  --output text)
if [ "$source_image_name" = "None" ]; then
  echo "Cannot find ${environment_ami_id}. Please contact AWS support if you need additional help: https://aws.amazon.com/support."
  exit 1
fi

copied_image_name="Copy of ${source_image_name}"
copied_ami_id=$(aws ec2 describe-images \
  --owners self \
  --filters Name=name,Values="${copied_image_name}" \
  --region "$REGION" \
  --query "Images[0].ImageId" \
  --output text)
if [ "$copied_ami_id" != "None" ]; then
  echo "Detected that ${environment_ami_id} has already been copied by account ${account}. Skipping image copy."
else
  echo "Copying ${environment_ami_id} to account ${account} with name ${copied_image_name}"
  copied_ami_id=$(aws ec2 copy-image \
    --source-image-id "$environment_ami_id" \
    --source-region "$REGION" \
    --name "$copied_image_name" \
    --region "$REGION" \
    --query "ImageId" \
    --output text)
  echo "New AMI ID is ${copied_ami_id}"

  echo "Waiting for ${copied_ami_id} to become available"
  aws ec2 wait image-available \
    --image-ids "$copied_ami_id" \
    --region "$REGION"
  echo "${copied_ami_id} is now available"
fi

echo "Updating environment ${ENVIRONMENT_NAME} to use ${copied_ami_id}"
environment_status=$(aws elasticbeanstalk update-environment \
  --application-name "$APPLICATION_NAME" \
  --environment-name "$ENVIRONMENT_NAME" \
  --option-settings "Namespace=aws:autoscaling:launchconfiguration,OptionName=ImageId,Value=${copied_ami_id}" \
  --region "$REGION" \
  --query "Status" \
  --output text)
echo "Environment ${ENVIRONMENT_NAME} is now ${environment_status}"

echo "Waiting for environment ${ENVIRONMENT_NAME} update to complete"
aws elasticbeanstalk wait environment-updated \
  --application-name "$APPLICATION_NAME" \
  --environment-names "$ENVIRONMENT_NAME" \
  --region "$REGION"
echo "Environment ${ENVIRONMENT_NAME} update complete"